ENVIRONMENTAL CHANGE

We monitored breeding anemonefish in their anemones in the lagoon of Moorea over 15 months before, during and after the predicted El Nino warming event in 2016. Half of the anemones hosting our monitored anemonefish bleached - a natural field experiment. Whilst temperature alone didn't impact anemonefish steroid hormones or reproduction, bleaching did. Male and female anemonefish living in bleached anemone still had elevated cortisol levels after 3 months, 11-ketotesterone levels and estradiol levels plummeted and reproduction stopped (Beldade et al 2017). Fortunately when the warming event ended and the anemones had recovered so did the anemonefish and reproduction returned to normal.

Thermal stressors on a coral reef fish's stress response

We visited the Iles Eparses in the Mozambique Channel on the Marion Dufresne and measured the cortisol response of skunk anemonefish, Amphiprion akallopisos, to a generic stressor. Reef populations on these islands are rarely exposed to any anthropogenic stressors, but have experienced different thermal histories over the last 15 years. We found that those fish populations exposed to higher maximum sea surface temperatures showed greater cortisol responses to a generic stressor. We suggest that the stress-responses axis could have been permanently modified following a thermal stressors event. Such a modification could be adaptive if repeated thermal stress events were common within a reef organism's lifetime (Mills et al., 2015).

Ocean acidification and thermal stressors

We are working on the effects of both ocean acidification and thermal stress on embyronic development in the sea hare, Stylocheilus striatus.

An elevated thermal environment accelerates planktotrophic development of this important benthic invertebrate, possibly at the cost of reducing fitness and increasing mortality (Horwitz et al., 2017). In collaboration withEric ArmstrongandJonathan Stillmanwe have also found that oceanic conditions congruent with climate change predictions for the end of the twenty-first century suppress successful development in S. striatus embryos, potentially reducing their viability as pelagic larvae (Armstrong et al, 2017).

We are also evaluating whether developmental /or transgenerational acclimation by Stylocheilus striatus, to the combined stressors will mitigate the effects on embyronic development.

In collaboration with Sophie Nedelec, Andy Radford and Steve Simpson from the Universities of Bristol and Exeter in the UK, we are investigating the effects of boat noise pollution on development, physiology and behaviour and whether marine organisms can habituate to boat noise.

In collaboration with Isabelle Côté, from Simon Fraser University, our "dream team" found that boat passage affects the honesty of the interactions between cleanerfish and their clients, despite cheating more, cleanerfish are not punished correspondingly (Nedelec et al., 2017).